Imagine this, You open your laptop, type chaicode.com, and press Enter. Within a second a page appears. Have you wondered how that page reached you? It didn’t just magically appear. Behind the scenes, some networking devices worked together like a team.

Let’s understand With a story

Internet starts from Outside your home

Think of the internet as a very big city full of information:

• Website
• Videos
• Apps
• Servers

Your home and office is just a small house in that city. To bring network into your house, we need some helpers.

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Modem – The Internet Door of Your home

First understand, What is Modem? A modem is the first device that connects your home to the internet.

Without a modem:

• No Internet
• No Website
• No YouTube

Let’s understand with a example Modem is like a main gate of your house It allows the internet to enter your home.

Internet comes from your ISP(Internet service provider) -> Jio, Airtel etc.. The modem understand their signals and convert them into data your device can use.

No modem == No internet

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Router - Who gets the internet?

Now the internet is inside your house. But you have:

• Mobile
• Laptop
• Smart TV

Who decides which gets what data? That’s the router job

What is Router? A router sends internet data to correct device. Example: Router is like a traffic police it sees:

• This data is for phone
• This is your laptop

And sends it correctly

• One internet connection
• Many devices
• Router manage everything

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Hub vs Switch - Talking Inside the network

Inside an office or lab, many computer are connected together. For this, we use hub and switch.

Let’s we will take an example of the classroom.

Hub -Old Style (Not Smart)

A hub sends data to everyone.

Teacher shouts a message in the class Even students who don’t need to hear it.

Problem:

• slow
• wastes data
• Not secure

Switch -Smart Choice

A switch sends data only the correct computer.

Example:

Teacher gives a letter to one student, Only that student reads it.

Benefits:

• Fast
• Secure
• Used everywhere today

Modern network use switches, Not hubs

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Firewall - The Security Guard

The internet is useful, but it is also dangerous. Hackers, viruses, unwanted traffic all exists. That’s why we need a firewall.

First understand, What is Firewall? A firewall checks every request coming in or going out.

See, Firewall is like a security guard at a gate

• Allowed person -> come in
• Unknown person -> Stop

Firewall protects:

• Computer
• Servers
• Database

Load Balancer -> Handling Too many users

Let’s take a example of Flipkart: Flipkart announced 80% discount of every product, Now what will happen Thousand of the people visits their website to purchasing products at a same time. One server will get tired So what do we do?

Here the concepts of load balancer comes?

What is load balancer? A Load Balancer shares traffic between many servers.

We see at Toll plaza on highway

• One gate -> traffic jam
• Multiple gats -> Smooth traffic

Load Balancer:

• Makes website fast
• Prevents server crash
• Used in big apps like Flipkart, Netflix

Short and precise meaning of all is:

1. Internet comes from ISP
2. Modem brings it inside
3. Router sends it to right device
4. Firewall checks security
5. Load balancer manages heavy traffic
6. Switch connects internal systems
7. Data reaches server
8. Response comes back to you